// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "cc/raster/one_copy_raster_buffer_provider.h"

#include <stdint.h>

#include <algorithm>
#include <limits>
#include <utility>

#include "base/macros.h"
#include "base/memory/ptr_util.h"
#include "base/metrics/histogram_macros.h"
#include "base/trace_event/trace_event.h"
#include "cc/base/histograms.h"
#include "cc/base/math_util.h"
#include "cc/resources/platform_color.h"
#include "cc/resources/resource_format.h"
#include "cc/resources/resource_util.h"
#include "cc/resources/scoped_resource.h"
#include "gpu/GLES2/gl2extchromium.h"
#include "gpu/command_buffer/client/gles2_interface.h"
#include "gpu/command_buffer/client/gpu_memory_buffer_manager.h"
#include "ui/gfx/buffer_format_util.h"

namespace cc {
namespace {

    // 4MiB is the size of 4 512x512 tiles, which has proven to be a good
    // default batch size for copy operations.
    const int kMaxBytesPerCopyOperation = 1024 * 1024 * 4;

} // namespace

OneCopyRasterBufferProvider::RasterBufferImpl::RasterBufferImpl(
    OneCopyRasterBufferProvider* client,
    ResourceProvider* resource_provider,
    const Resource* resource,
    uint64_t previous_content_id,
    bool async_worker_context_enabled)
    : client_(client)
    , resource_(resource)
    , lock_(resource_provider, resource->id(), async_worker_context_enabled)
    , previous_content_id_(previous_content_id)
{
    client_->pending_raster_buffers_.insert(this);
}

OneCopyRasterBufferProvider::RasterBufferImpl::~RasterBufferImpl()
{
    client_->pending_raster_buffers_.erase(this);
}

void OneCopyRasterBufferProvider::RasterBufferImpl::Playback(
    const RasterSource* raster_source,
    const gfx::Rect& raster_full_rect,
    const gfx::Rect& raster_dirty_rect,
    uint64_t new_content_id,
    float scale,
    const RasterSource::PlaybackSettings& playback_settings)
{
    TRACE_EVENT0("cc", "OneCopyRasterBuffer::Playback");
    client_->PlaybackAndCopyOnWorkerThread(
        resource_, &lock_, sync_token_, raster_source, raster_full_rect,
        raster_dirty_rect, scale, playback_settings, previous_content_id_,
        new_content_id);
}

OneCopyRasterBufferProvider::OneCopyRasterBufferProvider(
    base::SequencedTaskRunner* task_runner,
    ContextProvider* compositor_context_provider,
    ContextProvider* worker_context_provider,
    ResourceProvider* resource_provider,
    int max_copy_texture_chromium_size,
    bool use_partial_raster,
    int max_staging_buffer_usage_in_bytes,
    ResourceFormat preferred_tile_format,
    bool async_worker_context_enabled)
    : compositor_context_provider_(compositor_context_provider)
    , worker_context_provider_(worker_context_provider)
    , resource_provider_(resource_provider)
    , max_bytes_per_copy_operation_(
          max_copy_texture_chromium_size
              ? std::min(kMaxBytesPerCopyOperation,
                  max_copy_texture_chromium_size)
              : kMaxBytesPerCopyOperation)
    , use_partial_raster_(use_partial_raster)
    , bytes_scheduled_since_last_flush_(0)
    , preferred_tile_format_(preferred_tile_format)
    , staging_pool_(task_runner,
          worker_context_provider,
          resource_provider,
          use_partial_raster,
          max_staging_buffer_usage_in_bytes)
    , async_worker_context_enabled_(async_worker_context_enabled)
{
    DCHECK(compositor_context_provider);
    DCHECK(worker_context_provider);
}

OneCopyRasterBufferProvider::~OneCopyRasterBufferProvider()
{
    DCHECK(pending_raster_buffers_.empty());
}

std::unique_ptr<RasterBuffer>
OneCopyRasterBufferProvider::AcquireBufferForRaster(
    const Resource* resource,
    uint64_t resource_content_id,
    uint64_t previous_content_id)
{
    // TODO(danakj): If resource_content_id != 0, we only need to copy/upload
    // the dirty rect.
    return base::MakeUnique<RasterBufferImpl>(this, resource_provider_, resource,
        previous_content_id,
        async_worker_context_enabled_);
}

void OneCopyRasterBufferProvider::ReleaseBufferForRaster(
    std::unique_ptr<RasterBuffer> buffer)
{
    // Nothing to do here. RasterBufferImpl destructor cleans up after itself.
}

void OneCopyRasterBufferProvider::OrderingBarrier()
{
    TRACE_EVENT0("cc", "OneCopyRasterBufferProvider::OrderingBarrier");

    gpu::gles2::GLES2Interface* gl = compositor_context_provider_->ContextGL();
    if (async_worker_context_enabled_) {
        GLuint64 fence = gl->InsertFenceSyncCHROMIUM();
        gl->OrderingBarrierCHROMIUM();

        gpu::SyncToken sync_token;
        gl->GenUnverifiedSyncTokenCHROMIUM(fence, sync_token.GetData());

        DCHECK(sync_token.HasData() || gl->GetGraphicsResetStatusKHR() != GL_NO_ERROR);

        for (RasterBufferImpl* buffer : pending_raster_buffers_)
            buffer->set_sync_token(sync_token);
    } else {
        gl->OrderingBarrierCHROMIUM();
    }
    pending_raster_buffers_.clear();
}

ResourceFormat OneCopyRasterBufferProvider::GetResourceFormat(
    bool must_support_alpha) const
{
    if (resource_provider_->IsResourceFormatSupported(preferred_tile_format_) && (DoesResourceFormatSupportAlpha(preferred_tile_format_) || !must_support_alpha)) {
        return preferred_tile_format_;
    }

    return resource_provider_->best_texture_format();
}

bool OneCopyRasterBufferProvider::IsResourceSwizzleRequired(
    bool must_support_alpha) const
{
    return ResourceFormatRequiresSwizzle(GetResourceFormat(must_support_alpha));
}

bool OneCopyRasterBufferProvider::CanPartialRasterIntoProvidedResource() const
{
    // While OneCopyRasterBufferProvider has an internal partial raster
    // implementation, it cannot directly partial raster into the externally
    // owned resource provided in AcquireBufferForRaster.
    return false;
}

void OneCopyRasterBufferProvider::Shutdown()
{
    staging_pool_.Shutdown();
    pending_raster_buffers_.clear();
}

void OneCopyRasterBufferProvider::PlaybackAndCopyOnWorkerThread(
    const Resource* resource,
    ResourceProvider::ScopedWriteLockGL* resource_lock,
    const gpu::SyncToken& sync_token,
    const RasterSource* raster_source,
    const gfx::Rect& raster_full_rect,
    const gfx::Rect& raster_dirty_rect,
    float scale,
    const RasterSource::PlaybackSettings& playback_settings,
    uint64_t previous_content_id,
    uint64_t new_content_id)
{
    if (async_worker_context_enabled_) {
        // Early out if sync token is invalid. This happens if the compositor
        // context was lost before ScheduleTasks was called.
        if (!sync_token.HasData())
            return;
        ContextProvider::ScopedContextLock scoped_context(worker_context_provider_);
        gpu::gles2::GLES2Interface* gl = scoped_context.ContextGL();
        DCHECK(gl);
        // Synchronize with compositor.
        gl->WaitSyncTokenCHROMIUM(sync_token.GetConstData());
    }

    std::unique_ptr<StagingBuffer> staging_buffer = staging_pool_.AcquireStagingBuffer(resource, previous_content_id);

    sk_sp<SkColorSpace> raster_color_space = raster_source->HasImpliedColorSpace() ? nullptr
                                                                                   : resource_lock->sk_color_space();

    PlaybackToStagingBuffer(staging_buffer.get(), resource, raster_source,
        raster_full_rect, raster_dirty_rect, scale,
        raster_color_space, playback_settings,
        previous_content_id, new_content_id);

    CopyOnWorkerThread(staging_buffer.get(), resource_lock, sync_token,
        raster_source, previous_content_id, new_content_id);

    staging_pool_.ReleaseStagingBuffer(std::move(staging_buffer));
}

void OneCopyRasterBufferProvider::PlaybackToStagingBuffer(
    StagingBuffer* staging_buffer,
    const Resource* resource,
    const RasterSource* raster_source,
    const gfx::Rect& raster_full_rect,
    const gfx::Rect& raster_dirty_rect,
    float scale,
    sk_sp<SkColorSpace> dst_color_space,
    const RasterSource::PlaybackSettings& playback_settings,
    uint64_t previous_content_id,
    uint64_t new_content_id)
{
    // Allocate GpuMemoryBuffer if necessary. If using partial raster, we
    // must allocate a buffer with BufferUsage CPU_READ_WRITE_PERSISTENT.
    if (!staging_buffer->gpu_memory_buffer) {
        staging_buffer->gpu_memory_buffer = resource_provider_->gpu_memory_buffer_manager()->CreateGpuMemoryBuffer(
            staging_buffer->size, BufferFormat(resource->format()),
            StagingBufferUsage(), gpu::kNullSurfaceHandle);
    }

    gfx::Rect playback_rect = raster_full_rect;
    if (use_partial_raster_ && previous_content_id) {
        // Reduce playback rect to dirty region if the content id of the staging
        // buffer matches the prevous content id.
        if (previous_content_id == staging_buffer->content_id)
            playback_rect.Intersect(raster_dirty_rect);
    }

    // Log a histogram of the percentage of pixels that were saved due to
    // partial raster.
    const char* client_name = GetClientNameForMetrics();
    float full_rect_size = raster_full_rect.size().GetArea();
    if (full_rect_size > 0 && client_name) {
        float fraction_partial_rastered = static_cast<float>(playback_rect.size().GetArea()) / full_rect_size;
        float fraction_saved = 1.0f - fraction_partial_rastered;
        UMA_HISTOGRAM_PERCENTAGE(
            base::StringPrintf("Renderer4.%s.PartialRasterPercentageSaved.OneCopy",
                client_name),
            100.0f * fraction_saved);
    }

    if (staging_buffer->gpu_memory_buffer) {
        gfx::GpuMemoryBuffer* buffer = staging_buffer->gpu_memory_buffer.get();
        DCHECK_EQ(1u, gfx::NumberOfPlanesForBufferFormat(buffer->GetFormat()));
        bool rv = buffer->Map();
        DCHECK(rv);
        DCHECK(buffer->memory(0));
        // RasterBufferProvider::PlaybackToMemory only supports unsigned strides.
        DCHECK_GE(buffer->stride(0), 0);

        DCHECK(!playback_rect.IsEmpty())
            << "Why are we rastering a tile that's not dirty?";
        RasterBufferProvider::PlaybackToMemory(
            buffer->memory(0), resource->format(), staging_buffer->size,
            buffer->stride(0), raster_source, raster_full_rect, playback_rect,
            scale, dst_color_space, playback_settings);
        buffer->Unmap();
        staging_buffer->content_id = new_content_id;
    }
}

void OneCopyRasterBufferProvider::CopyOnWorkerThread(
    StagingBuffer* staging_buffer,
    ResourceProvider::ScopedWriteLockGL* resource_lock,
    const gpu::SyncToken& sync_token,
    const RasterSource* raster_source,
    uint64_t previous_content_id,
    uint64_t new_content_id)
{
    ContextProvider::ScopedContextLock scoped_context(worker_context_provider_);
    gpu::gles2::GLES2Interface* gl = scoped_context.ContextGL();
    DCHECK(gl);

    // Create texture after synchronizing with compositor.
    ResourceProvider::ScopedTextureProvider scoped_texture(
        gl, resource_lock, async_worker_context_enabled_);

    unsigned resource_texture_id = scoped_texture.texture_id();
    unsigned image_target = resource_provider_->GetImageTextureTarget(
        StagingBufferUsage(), staging_buffer->format);

    // Create and bind staging texture.
    if (!staging_buffer->texture_id) {
        gl->GenTextures(1, &staging_buffer->texture_id);
        gl->BindTexture(image_target, staging_buffer->texture_id);
        gl->TexParameteri(image_target, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        gl->TexParameteri(image_target, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        gl->TexParameteri(image_target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        gl->TexParameteri(image_target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    } else {
        gl->BindTexture(image_target, staging_buffer->texture_id);
    }

    // Create and bind image.
    if (!staging_buffer->image_id) {
        if (staging_buffer->gpu_memory_buffer) {
            staging_buffer->image_id = gl->CreateImageCHROMIUM(
                staging_buffer->gpu_memory_buffer->AsClientBuffer(),
                staging_buffer->size.width(), staging_buffer->size.height(),
                GLInternalFormat(resource_lock->format()));
            gl->BindTexImage2DCHROMIUM(image_target, staging_buffer->image_id);
        }
    } else {
        gl->ReleaseTexImage2DCHROMIUM(image_target, staging_buffer->image_id);
        gl->BindTexImage2DCHROMIUM(image_target, staging_buffer->image_id);
    }

    // Unbind staging texture.
    gl->BindTexture(image_target, 0);

    if (resource_provider_->use_sync_query()) {
        if (!staging_buffer->query_id)
            gl->GenQueriesEXT(1, &staging_buffer->query_id);

#if defined(OS_CHROMEOS) && defined(ARCH_CPU_ARM_FAMILY)
        // TODO(reveman): This avoids a performance problem on ARM ChromeOS
        // devices. crbug.com/580166
        gl->BeginQueryEXT(GL_COMMANDS_ISSUED_CHROMIUM, staging_buffer->query_id);
#else
        gl->BeginQueryEXT(GL_COMMANDS_COMPLETED_CHROMIUM, staging_buffer->query_id);
#endif
    }

    // Since compressed texture's cannot be pre-allocated we might have an
    // unallocated resource in which case we need to perform a full size copy.
    if (IsResourceFormatCompressed(resource_lock->format())) {
        gl->CompressedCopyTextureCHROMIUM(staging_buffer->texture_id,
            resource_texture_id);
    } else {
        int bytes_per_row = ResourceUtil::UncheckedWidthInBytes<int>(
            resource_lock->size().width(), resource_lock->format());
        int chunk_size_in_rows = std::max(1, max_bytes_per_copy_operation_ / bytes_per_row);
        // Align chunk size to 4. Required to support compressed texture formats.
        chunk_size_in_rows = MathUtil::UncheckedRoundUp(chunk_size_in_rows, 4);
        int y = 0;
        int height = resource_lock->size().height();
        while (y < height) {
            // Copy at most |chunk_size_in_rows|.
            int rows_to_copy = std::min(chunk_size_in_rows, height - y);
            DCHECK_GT(rows_to_copy, 0);

            gl->CopySubTextureCHROMIUM(
                staging_buffer->texture_id, 0, resource_texture_id, 0, 0, y, 0, y,
                resource_lock->size().width(), rows_to_copy, false, false, false);
            y += rows_to_copy;

            // Increment |bytes_scheduled_since_last_flush_| by the amount of memory
            // used for this copy operation.
            bytes_scheduled_since_last_flush_ += rows_to_copy * bytes_per_row;

            if (bytes_scheduled_since_last_flush_ >= max_bytes_per_copy_operation_) {
                gl->ShallowFlushCHROMIUM();
                bytes_scheduled_since_last_flush_ = 0;
            }
        }
    }

    if (resource_provider_->use_sync_query()) {
#if defined(OS_CHROMEOS) && defined(ARCH_CPU_ARM_FAMILY)
        gl->EndQueryEXT(GL_COMMANDS_ISSUED_CHROMIUM);
#else
        gl->EndQueryEXT(GL_COMMANDS_COMPLETED_CHROMIUM);
#endif
    }

    const uint64_t fence_sync = gl->InsertFenceSyncCHROMIUM();

    // Barrier to sync worker context output to cc context.
    gl->OrderingBarrierCHROMIUM();

    // Generate sync token after the barrier for cross context synchronization.
    gpu::SyncToken resource_sync_token;
    gl->GenUnverifiedSyncTokenCHROMIUM(fence_sync, resource_sync_token.GetData());
    resource_lock->set_sync_token(resource_sync_token);
    resource_lock->set_synchronized(!async_worker_context_enabled_);
}

gfx::BufferUsage OneCopyRasterBufferProvider::StagingBufferUsage() const
{
    return use_partial_raster_
        ? gfx::BufferUsage::GPU_READ_CPU_READ_WRITE_PERSISTENT
        : gfx::BufferUsage::GPU_READ_CPU_READ_WRITE;
}

} // namespace cc
